The grant is being requested to: 1) support the synchronization of multiple monitors used in labor and 2) establish the norms for the following physiologic variables during the second stage of labor: maternal heart rate, respirations, and oxygen saturation, uterine activity (contractions and bearing-down efforts) and fetal heart rate. Currently, medical caregivers primarily use technology and norms designed with high-risk women in labor. This hampers efforts to accurately assess the physiological responses to the normal birth process in low-risk women. The immediate outcome of this project will be the calibration of a polygraph which will be able to synchronously record the variables of interest in a manner that will permit the determination of a typical value and range for each variable in the target population. This will be followed by the identification of norms for physiological variables developed in a convenience sample of 100 healthy women in normal labor. The norms developed will be used as the baseline in future experimental trials contrasting the influence of various care practices (e.g., maternal position, bearing-down efforts, and epidural anesthesia) on these physiological variables.